Mountfield R28M Ride-on-Mower Mistake? Any tips..?

Section62

sujsuj said:

I will be getting new one tomorrow.

Don't put the new spark plug in the engine yet - there's a good chance that one will be wrecked as well.

Start by doing what ThisIsWeird has suggested and giving the old plug a proper clean.  Then whilst the plug is still out of the engine, connect it back onto the (electrical) lead and rest the plug on a metal part of the engine so there is good contact between the outer part of the plug and the engine.  This will complete the circuit so you will be able to see/hear whether the spark plug works when the engine turns over.  Now, bearing in mind the sparking system operates at very high voltage - i.e. DON'T TOUCH THE PLUG WHILE DOING THIS - turn the engine over using the starter while observing whether or not there is a spark on the plug.  Also make absolutely sure there is no petrol nearby as the spark could ignite it.

If you do get a reasonable spark then the problem isn't with the spark plug.

If you don't get a spark then either the plug is not clean enough, or you have an electrical fault.

So now repeat the process with the new spark plug.  Stressing here that you still shouldn't screw the spark plug back into the engine yet.

If the new spark plug works then you can be reasonably confident that the problem was the old one wasn't clean enough.

Bear in mind that the cylinder will still contain a lot of excess oil, and it is likely oil has got into the carburettor, so the first five minutes or so the engine runs it will produce a lot of smoke.  Whilst that is happening it will be taking years of life away from the new spark plug - hence don't put the new plug in until you are sure you need to and that you've already done as much as you can to get rid of the oil.

If oil has got into the carburettor then the reason for the engine not firing may be due to fuel starvation rather than a lack of spark.  Please don't try taking the carburettor apart and cleaning it though as it is incredibly easy to do permanent damage to them.  If you get a spark but the engine still won't start then get a professional to look at it before you inadvertently do any more damage.

Nobbie1967

Might be an idea to take off the air filter and spray some ‘Easystart’ into the inlet before trying to start it. It’s much more volatile than petrol and can often get a recalcitrant engine firing sufficiently to get fuel moving properly through the carburettor. You could also spray the spark plug with it to clean off the oil.

sujsuj

 
Got new spark plug, but still haven't got the result we needed.
Spark plug looks the same though different vendor.

Got Briggs & Stratton 992304 instead of champion rc12yc. I can see they are compatible

https://youtube.com/shorts/l025_C5QgK8

Thinking about the plan -B ; Any thing else to try..? Please help.

sujsuj

https://youtube.com/shorts/l025_C5QgK8

ThisIsWeird

sujsuj said:

 
Got new spark plug, but still haven't got the result we needed.
Spark plug looks the same though different vendor.

Got Briggs & Stratton 992304 instead of champion rc12yc. I can see they are compatible

https://youtube.com/shorts/l025_C5QgK8

Thinking about the plan -B ; Any thing else to try..? Please help.

You've been told what Plan B is.

And S62 has added to it.

And Bobbie has suggested another tac. But try the first bits first. 

S62 has also explained how to check the sp is actually sparking.

sujsuj

see some more photos..

sujsuj

should I put some force to make spark plug connector close to body so that there is a connection..? Not sure to me how it was before but I can see a gap between connector and engine body..? Not sure if that supposed to be closer . Since there is a gap inside spark plug end may not be touching the connector properly..?? Any suggestions..?? Thanks

Section62

sujsuj said:

should I put some force to make spark plug connector close to body so that there is a connection..? Not sure to me how it was before but I can see a gap between connector and engine body..? Not sure if that supposed to be closer . Since there is a gap inside spark plug end may not be touching the connector properly..?? Any suggestions..?? Thanks

If you do the thing I suggested in my previous post you'll know whether that is a problem or not.

Fixing things is a logical process.  You can either try random things and hope you get lucky, or you follow the logical process until you've eliminated the fault.

The problem with the random approach you are following is you end up breaking other things and costing yourself more time and money.

Up to you which approach to adopt though.

TELLIT01

Although there is going to be some cost involved, I really think it's time to call in the professionals.  I have understood the instructions given so far, but wouldn't want to mess about any further for fear of doing more damage.

benson1980

My next steps would be:
- test of spark plug good shout
- did you check the air filter for and oil/fuel residue? 
- I would check and clean the carb (can of carb cleaner required). Accepting you need to be careful with it, it isn't that difficult.
- with the blade and mentioning you tried to loosen it, is it fully secure on the crankshaft? This is essentially part of the flywheel so a loose blade can cause problems starting, as I recently discovered with our mower.

Is there a correct way to tilt this machine? The instructions will surely tell you. It's always air filter up on a push mower.

I'd be inclined to say you've got this far so may as well crack on and try and fix it yourself, or at least try the basic steps that have been suggested before calling a repair shop.